From Gardener's Supply (www.gardeners.com)

Asian Lady Beetles — More Than a Nuisance

This Introduced Species is Harming Native Lady Beetles

By Suzanne DeJohn, Employee Owner
Asian lady beetle
Asian lady beetle. Photo: Whitney Cranshaw, Colorado State University, Bugwood.org, author of Garden Insects of North America

Of the thousands of species of lady beetles in the world, several hundred can be found in the U.S. Some are native species, and some, such as the Asian lady beetle, were intentionally introduced to help control crop pests. Unfortunately the tables have turned and this introduced species itself has become a pest.

During the 1960s through the 1990s, the U.S. Department of Agriculture released large numbers of Asian lady beetle in an effort to manage aphids and scale insects on pecans and apples, among other crops. Though the releases took place in specific states across the country, the beetles' have spread and their range now includes most of the U.S.

Asian Lady Beetles Are a Nuisance — and More

Both Asian lady beetles and native species, such as the convergent lady beetle, hunt garden pests. However, Asian lady beetles have become a troublesome pest in many parts of the country:

Native Lady Beetles Asian Lady Beetles
  • Tend to seek shelter outdoors
  • Don't gather in large numbers
  • Don't bite
  • Don't smell bad
  • Invade homes in fall
  • Congregate in large numbers, especially around warm, sunny windows
  • May inflict a small bite
  • When they feel threatened, they exude a foul-smelling liquid that can stain surfaces

Asian lady beetles are believed responsible, at least in part, for the severe decline in the populations of native lady beetles. Often larger than their native counterparts, Asian lady beetles not only outcompete their cousins for food, they actually prey on the native species. Asian lady beetles vary widely in color (orange, pinkish, red) as well as number and shape of spots. The distinguishing feature is a black, M-shaped mark behind the head:

Asian lady beetle identification
Asian lady beetles. Note the M-shaped mark on the head. Photos: Scott Bauer, USDA Agricultural Service, Bugwood.org, and Whitney Cranshaw.
Related Article: Beneficial Insects: Ladybug / Lady Beetle

Our Ladybug Buster: Effective, Nontoxic Control

Ladybug Buster
Our Ladybug Buster is a nontoxic and longlasting way to control Asian Lady Beetles. Simply install the inconspicuous traps in a window where the insects congregate.

Last updated: 4/29/19


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